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I need HELP… Please
« on: November 14, 2014, 08:43:53 PM »
Hi all.

I need HELP… I have been diagnosing a glitch in my CNC for weeks now and am completely stumped.

I'm having a regular fault with my X axis only.

I have spent a bit of time trouble shooting the problem and changing over parts, cables, adjusting settings and so on but can get it sorted.

Today I bought a rather expensive UPS, the type that isolate the input from the output as I though there could be an interference issue going on between the power supplies and my smooth stepper + Break out board.
This didn’t help unfortunately.

Background and parts: The machine is a rebuild from an old analogue system, I’m using identical setups on the X and Z with an AC servo on the Z. X has big issues, Y has no issues whatsoever and Z is fine.

Break out board: CNC4PC C32
Smooth steeper, USB To laptop
Running full version of Mach 3
X&Y Power supply: 48V 12A
X&Y Servo Controller:  DG4S
Motor: Brushed DC Servo
Encoder: AMT103

What’s going wrong: The X axis faults with movement, slow, fast with no load it faults and stops responding to Mach 3 inputs for a second or two. Once things stop physically moving it starts up again and responds to inputs. Mach hasn’t registered the fault had has continued to move in the program. 
The X setup works flawlessly in the servo configuration software and has no problems moving fast, slowly or accurately. The fault only occurs when controlled through the breakout board and smooth stepper.

What I’ve tried to resolve it:
Changing drivers: No change
Changing Encoders: No change
re running leads: No change
Using the Y output on breakout board and reconfiguring: No change
Powering all the low voltage, sensitive stuff with an isolated UPS: No change
Updating firmware: No change

I think it’s very much an X setup problem but not between the servo controller and the motor. That leaves the BOB + Smooth Stepper and the X setup causing interferences.

So yes, I’m stumped… If you know what’s going on please let me know.


Offline BR549

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Re: I need HELP… Please
« Reply #1 on: November 14, 2014, 09:36:18 PM »
OK IF you say that Y Works fine and you switch the X drive over to the Y output then THAT rules out the the PC and BOB as it still faults. That leaves the drive and motor.

I would switch the X motor with Y motor  to rule it out. IF it still does it then it is the drive itself.

You could then switch drives with Y to verify.

Just a thought, (;-) TP
Re: I need HELP… Please
« Reply #2 on: November 14, 2014, 11:49:23 PM »

Thanks for that.

Just thinking it through for myself. I had the Y driver controlling the X motor from the BOB and it had the same issue it’s always had in the normal X configuration. Both drivers work 100% fine with either motor or combination if they are being controlled by the servo software so I don’t think the drivers or the motors that are the issue?

I have some old DG2S drivers that I could try using, I’m not sure if they work but I’ll give it a shot.

Cheers, Dave
Re: I need HELP… Please
« Reply #3 on: November 17, 2014, 05:49:16 AM »
Well I gave the old drivers a go, they are cactus. I’ve email my supplier that I purchased all my gear from so hopefully they can help.   :-\
Re: I need HELP… Please
« Reply #4 on: November 17, 2014, 05:07:59 PM »

If the is issue is just with one axis, I would start swapping axis, driver, motors, cables, etc.  until you have singled out the issue.

Here are some thoughts:

- Your driver setup looks fine, but if the motors are the same, I would load the configuration from one of the drivers that are OK.
- Could it be something mechanical with the axis?
- Is the axis is truly faulting? What happens if you move the jumper to HARD ENABLE?

Please check this and let me know how it goes.

Arturo Duncan
Re: I need HELP… Please
« Reply #5 on: November 20, 2014, 02:45:39 AM »
Hi Arturo,

I don’t think it’s a problem with the axis, motor or cables. Both X and Y run faultlessly with the servo configuration software.

I changed the cables for both power and encoder to the motor. This hasn’t changed a thing.  It runs perfectly if it’s being controlled by the tuning software and faults constantly in both hard and soft enable when controlled by Mach3.

As I use the fly out jog control in Mach3 I can hear the BOB switching into a fault mode as the relays cut out? Not sure if this helps? Could it be a dip switch or solid contact that’s in the wrong place?


Re: I need HELP… Please
« Reply #6 on: November 20, 2014, 07:27:52 AM »

If you are concluding that it could be something in the breakout board settings, I will presume you have already swapped the cables going from the breakout board to the driver, and the problem stayed with the same axis on the breakout board.

Please confirm this is the case.

Arturo Duncan
Re: I need HELP… Please
« Reply #7 on: November 28, 2014, 05:10:25 AM »

I’m not concluding anything… I wish I was that far down the diagnosis track.

I think I swapped them over but I will double check and get back to you.

In the instance that the cables are ok would it be possible to send you setup files and get your opinion?

Re: I need HELP… Please
« Reply #8 on: November 29, 2014, 01:01:02 PM »

I do not think you need any files from me.  The idea is that you swap axes, cables, drivers, etc...  And what what follows the problem.

Let me know how it goes.

Arturo Duncan
Re: I need HELP… Please
« Reply #9 on: December 01, 2014, 04:50:12 AM »
Hi Arturo,

The cable swap didn’t help unfortunately.

What I was proposing was I send you my files and you have a look to see if anything is a miss. I would also send you a high resolution image or several high resolution images of my setup on the board showing the dip switches.

If through your after sales support we can’t fix it I’ll need to start replacing hardware as I’ve already changed all the wiring and swapped bits over.